An attempt to force the Government to include a 2030 decarbonisation target in the Energy Bill was defeated in the House of Lords.
Peers last night rejected by 216 votes to 202, Government majority 14, a move to insist a target to substantially decarbonise electricity generation by 2030 is introduced by next April rather than the current plan to consider introducing a target in 2016.
A similar amendment to the Energy Bill was defeated in the House of Commons in June.
Labour shadow energy minister Baroness Worthington argued that without the amendment the Bill was "largely lacking in purpose", but energy minister Baroness Verma said a target should not be "rushed into" as it would have "significant implications for the power sector, consumers and the wider economy".
Lady Worthington told peers during report stage debate: "This amendment is about timing and I believe it is right to set this target now. Without bringing forward the setting of this target, this Energy Bill is largely lacking in purpose.
"It is a very enabling Bill including many measures that will enable the Secretary of State to do things at his or her discretion but it doesn't require anybody to do anything very specific.
"So, despite the fact we have been deliberating over this Bill for years, the investors are not celebrating the fact it is almost complete, they are not yet clear about what this Bill actually delivers.
"There is still insufficient clarity of purpose, too much doubt about the Government's commitment to cleaning up and modernising our energy sector and too much control now being given to Government; a Government that is unfortunately equivocating about the need for low carbon investment."
Leading scientist Lord Oxburgh, who put forward the amendment, said it was "about getting on with the job, setting milestones for ordered progress to a new energy structure and specifically setting a decarbonisation milestone for 2030".
The independent crossbench peer added: "The milestones should be set for no other reason that the sooner it is set the less expensive it will be to achieve energy security and decarbonisation. Accepting the amendment is the no regrets course.
"Should some miraculous game-changing new technology appear or some other unforeseen circumstance arise, the Bill as drafted provides ministers with ways of dealing with the unexpected. There is simply no reason not to get on with the job that has to be done and every reason for doing it now. The amended Bill would be good for jobs, UK industry, investment and for the environment."
But Lady Verma told peers: "A target is not something that should be rushed into. A target would have significant implications for the power sector, consumers and the wider economy.
"It is therefore vital to understand fully, based on evidence, whether a target represents the best approach to meeting our economy-wide carbon budgets cost effectively and if so what level it should be set at.
"The right time to consider this is in 2016, not in 2014 as proposed by the amendment."
She said that in 2016 in line with the Carbon Change Act the Government would undertake "extensive analysis to set the level of the fifth carbon budget in law".
"At this point we can consider a decarbonisation target within the broader context of the trajectory of our whole economy to our 2050 target (to cut emissions by 80 per cebt from 1990 levels)," she argued.
Friends of the Earth executive director Andy Atkin said: "By voting against a clean power target, the Lords are saddling us with an Energy Bill that's bad news for bill-payers, the economy, and the climate; letting the Big Six energy suppliers off the hook.
"Putting off the decision on a target until at least 2016 will continue to undermine investor confidence in the UK's energy market and risk driving much-needed business and jobs abroad.
"The Liberal Democrats have played a sorry part in this decision; shamefully, this is the second time they've blocked a clean power target, despite claiming to support it all along."
Report stage debate was later adjourned until next Monday.